Voltage regulating equipment



y 1937. v J. w. GRAFF ET AL I 2,079,206

VOLTAGE REGULATING EQUIPMENT Filed Nov. 22, 1955 INVENTORS Patented May4, 1937 UNIT-so STATES PATENT orr ca e e tenses my fiemmmrt I e I. e

1 Joseph W. Grail, ,Homewood, and Samuel J.

Spurgeon, Birmingham, Ala., assignors of onethird to Southern StatesEquipment 00., Bir- I a mingham, Ala.

- "Application November 22, 1935, Serial No. 51,020

6 Claims. on. 171-119) One purpose of this invention is to provideatransformer means whereby the voltage 'of a circuit for the distributionot'electrical energy may be increased automatically when the load in the5 circuitis increased and thevoitage tends to decrease, thereby tendingto prevent excessive voltage drop-in parts of the circuit fed by thetransformer.- Another purpose'is to provide a transformer of which thesecondary output remains in constant =in-voltage although the supplyvoltage to it may vary over a given range. Another purpose is to'provide a voltage regulator'appiicabie for use remote from the source ofpower, whereby voltage" at the distant end of a circuitbeyond theregulator may be automatically increased when the'load in the-circuithas increased. And

another object 5 is to-attain' the above results without the use ofmovable coils, cores, or similar main members. However, this does notpreclude oi the equipment";

One of the principles used in the invention is to regulate themagnetic-fluxinone part of a magnetic circuit in accordance withvariations in the voltage in a conducting circuit,*andby this regulationto modify the magnetic flux in an adjacent magnetic path; this lastmodification producing the desired changes in voltage in a conductorwhich surrounds the said adjacent magnetic path, which conductor is inseries with the output circuit.

Referring to the drawing, the' single figure shows in diagram onearrangement of apparatus in which the invention is embodied.

" The drawing shows an iron'transformer core A, B, C,-D, E, F, G, H, J,K, pause: which are encircledby the primary winding I, thesecon'darylwinding 2, the regulating winding 3, and

the controlwindings'-4,'5, 6 and 1. The input is over the conductors 8;9 and theoutput is over a the conductors l0, ii. Connected in the outputcircuit l0, ii is the regulating winding 3 which encircles the G portionof the core.

and 5 are in series, and they are connected 5 through the conductors i2,13 into a closed circuit with the variable'reactor ll.

The coils of H which are in circuit with l2, ii are wound in series withone another, and the magnetic flux tends to flow as shown by the arrows,or else the reverse. The middle coil of II is connected through theconductors i5, ii to the regulating devices. Connected to the circuitIII, II is the bridge l'l comprised of two resistors ll of lowtemperature coefficient and two resistors ll of high-temperaturecoefllcient, such the use of movingparts in the control'members netizingcurrents. through the The coils 4,

has lamps. One mid point onthe'bridge is connected through I8 to'thegrid of vacuum tube 24; and the other midpoint, through i9 connected toone end of the secondary of transformer 20. The primary of transformer"is energized from the circuit II, II. The plate-circuit oithe vacuumtube 24 is connected'to the grid of the vacuum tube 45, and "thecondenser 25 and other parts are connected as shown. ';As described inElectronics for March; i934,v such "equipment will operate to causeunidirectional pulsating current to'ilow through the'circuit [5,liwhenever the voltage of thecircuit illfli .drops below the voltageatwhich the bridge atil is balanced. A similar bridge is also, connectedto the .circuitill, II, but thelamps and resistors aretr'ansposed ascompared with thebr idge llfari'd therefore it is when the voltage incircuit 10, ll rises above the balance point thatzdire'c't current flowsthrough'the circuit 21, 28. Between the bridge and itscontrolled circuitis connected through a the conductors 30, H to the coils 6, 1.

Operation is as follows: v When the load on the main transformer and theprimary voltage on the circuit 8, 9 are such that the desired secondaryvoltage is maintained on the circuit Ni, H, with the current flow in atl and out at 9, the magnetic flux in the core will be up in A, rightinB' and E, down in C, D, J, and K, and left in H and There will be noflux through G, except that due to the current flow in the coil 3, forthe high reactance of H and 29 prevent the flow of any. current, exceptmagcontrol coils l,5,i,|.

Now when low primaryvoltage, .or an increase of load on the secondarycircuit, produces conditionsfof low secondary voltage, the regulatingbridge I! and the associated equipment send current through the circuit[5, I6. Thisiends to magnetize with direct current the core ofthereactor ll, so that less flux can pass through it in response to theflow of magnetizing current in the circuit i2, i3. Therefore thereariance of the reactor H is reduced and some induced cur rent isallowed to now through the coils 4, 5.

The magnetomotive force of this induced current opposes and subtractsfrom the flux which produces it, and so diverts some flux through J, andD. This reduction of flux in C and K and the increase through J and D,force flux through G from right to left, at the assumed instants whencurrent flow is in at I and out at 0. At each alternation, thedirections of current flow and magnetic ilux are changed, butthe'assumed instants are the same throughout this specification. Thisflux through G produces in coil I a voltage which supplements thevoltage of the coil 2, and so the voltage in circuit II, II is raisedvery nearly to normal.

Conversely, when higher voltage is present in the circuit III, II, thebridge It acts to produce direct current'in the circuit 21, 2'. This inturn increases the flow of current in the coils C, 1, and the net resultis a greater flux through C, G, K, H. This flux from left to rightthrough G creates in the coil 3 a voltage that subtracts from thevoltage of the coil 2, and so voltage oi the circuit IO, N is reduced tosubstantially normal.

Depending upon the proportions of the windings and the voltages applied,the balance of magnetic flux at diflerent instants may vary somewhat,and when it is said that flow of current in a coil produces a certainmagnetic flux it is meant that it produces a magneto-motive force inthat direction; and this tendency may result either in the actualproduction of flux as stated. or it may merely reduce the flux which isalready flowing in the opposite direction. Also when it is said thatthere is a flow of current in one direction, it is understood that thereis a tendency for current to flow in that direction, and if some currentwas already flowing in the opposite direction, the net result may merelybe a reduction of the latter current. In either case, the effectsproduced upon the final results are the same, and this explanationapplies throughout the specification and claims.

By proper proportioning of the members, and adjustment of the controlequipment, the applied voltage of the secondary circuit is increasedwhen the load increases and decreased when the load decreases, so that arelatively stationary voltage is maintained at terminals of the circuitII, II, where lamps, motors, and other appliances are being used. Sincethe control as described is electrical, rather than electro-mechanical,thechanges in regulation occur immediately and automatically and withoutany motion oi any of the coils or cores oi. the. transformer.

For heavys'zes oi equipment there are some advantages in the use ofelectro-mechanical control devices for the application of theflux-shitting currents to the transformer core. For this purpose, asuitable contact-making voltmeter operating a small motor-operatedrheostat in the unidirectional or D. C. circuit may be used withoutdeparting from the spirit or purpose of this invention.

We have shown only a few methods of using this invention: and there aremany modifications which can readily be made in the various parts of theequipment here described, without departing from the spirit and purposeof the invention,

We claim:

1. voltage regulating equipment comprising an incoming exciting circuit,an outgoing circuit, a closed magnetic path surrounded by the saidexciting circuit, one portion of the said path consisting oi twobranches joined together at both ends, a cross-path connecting the midportions of the said branches, 1. regulating winding surrounding thesaid cross-path and connected in series with the outgoing circuit,together with means to change the relative direction of magnetic flux inthe said cross path.

2. Voltage regulating equipment comprising an incoming exciting circuit,an outgoing circuit, a closed magnetic path surrounded by the saidexciting circuit, one portion oi the said path consisting of twobranches joined together at both ends, a cross-path connecting the midportions of the said branches, a regulating winding surrounding the saidcross-path and connected in series with the outgoing circuit, togetherwith automatic means to change the relative direction of magnetic fluxin the said cross-path in coordination with changa. in the voltage ofthe said exciting circuit.

3. In voltage regulating equipment, a closed magnetic circuit, oneportion of which consists oi two magnetically parallel branches with across-path connecting the mid-portions oi the said branches, aregulating coil about the said cross-path and in series with a regulatedcircuit, together with means to change the relative direction ofmagnetic flux through the said cross-path.

4. In voltage regulating equipment, a closed magnetic circuit, oneportion of which consists of two magnetically parallel branches with across-path connecting the mid-portions oi the said branches, aregulating coil about the said cross-path and in series with a regulatedcircuit, together with control coils about the said parallel branches ofthe magnetic circuit.

5. In voltage regulating equipment, a closed magnetic circuit, oneportion oi which consists of two magnetically parallel branches with across-path connecting the mid-portions oi the said branches, aregulating coil about the said cross-path and in series with a regulatedcircuit, together with control coils about the said parallel branches ofthe magnetic circuit, said control coils being operable when. energizedto change the relative polarity of the voltage developed in the saidregulating coil.

6. In voltage regulating equipment, a closed magnetic circuit, oneportion of which consists of two magnetically parallel branches with across-path connecting the mid-portions of the said branches, aregulating coil about the said cross-path and in series with a regulatedcircuit, together with automatic means to change the relative directionof magnetic flux through the said cross-path in coordination withchanges of voltage in the regulated circuit.

JOSEPH w. 0am. SAMUEL J. SPURGEON.

